Mel Brooks's favourite London restaurant is a small Chinese in Soho (but he draws the line at duck feet). Photographs by Dominick Tyler
When Mel Brooks visits London he's accustomed to the very best. He enjoys royal treatment at his hotel of choice, The Savoy, and is on friendly terms with the maitre d's of most of the city's finest restaurants. So when I asked him to nominate a favourite dining-spot, I was slightly taken aback by his choice - New Diamond in Soho, one of the scores of inexpensive and largely indistinguishable Cantonese restaurants which line the streets of Chinatown.

"I was doing a show with Joan Collins, and her manager told me the best Chinese food in the world is at New Diamond in Lisle Street. And he was right," Mel rasped, as he tucked his tie between the buttons of his shirt and set about the serious business of ordering.

Despite booking a table in the main ground-floor dining room, the four of us - Mel and I, plus mutual friends Alan Yentob of the BBC and his partner Philippa - had been consigned to the rather musty basement, and given the choice of two tables, one by the kitchen, the other by the toilets. From the open kitchen door drifted the whiff of ammonia, along with an occasional burst of loud and phlegmy hawking. "It's very ... authentic," ventured Alan, whose idea of casual dining is arriving at The Ivy without a reservation.

New Diamond's menu is a laminated 10-pager, which kicks off gently enough with spring rolls, and soars to the outer limits of fantasy with dishes like stewed fish head with bean curd, and boiled geoduck with jellyfish. Mel and I were soon locked into a power struggle; I wanted to be adventurous, but he had his own ideas. "How much seafood are you gonna order - I just wanna know right now!" he challenged when I ventured a few choices. Then our waiter got in on the act, knocking back another of my suggestions, chicken, salted fish and aubergine hot pot. "It has a very strong taste," he warned. "And a very strong smell." "You won't like that!" Mel interrupted confidently. "We should have noodles instead!"

I'd been warned that New Diamond's staff can be unfriendly, but our waiter couldn't have been more helpful, supplementing our choices with his own suggestions. From the daily specials, he recommended something called "laser crabs", which we all agreed sounded deliciously exotic. But when he kept repeating "no! crabs! CRABS!", with mounting frustration, we realised he was actually saying "razor clams".

An allergy to some shellfish prevented Mel from appreciating the clams, but he enjoyed watching us eat them. They were served steamed in their long, elegant shells, and had a delicate taste and squid-like texture. Scallops, still attached to their shells, were also steamed with perfectly judged precision, and Philippa and I agreed that they were as good as we'd ever had. "Everything here is the best thing you've ever had!' Mel enthused.

Next up were crispy Peking duck and the fattier Cantonese duck - the shiny, lacquered kind you see dangling corpse-like in the restaurant windows of Chinatown. Then came a bowl of limpid golden liquid which we initially took to be chicken broth. Embarrassingly, it turned out to be the finger-bowl, scented with tea, and intended to accompany the whole crab which arrived next. "Is it a boy crab or a girl crab?" Philippa asked the waiter. "It's a baked crab," he replied, bringing the discussion smartly to a close. "Uncompromisingly sensational," was Mel's verdict, which held good for the procession of dishes which followed - chilli-spiced squid, smoky lo mein noodles with pork, and crisp Chinese broccoli, which Mel promised would act as "a whisk broom for the intestinal tract".

Mel was on a flying visit to London to work with the British director Mike Ockrent on turning The Producers into a Broadway musical. "I'm as busy as sin," he lamented. "All I do is work and weep. Every night I pray for creativity, inspiration, and no urinary blockage." He started to talk us through the musical's opening scenes, complete with songs, but every time he got going, a new dish would arrive, or one of the restaurant's other customers would come up to pay their respects.

In fact, a stream of visitors approached our table over the course of the evening, the bolder ones asking for autographs, others just filing past to a get a look at him.

I'd managed to sneak a surprise into our order, a hot pot of braised duck web with fish lips. "Oh my God!" sighed Mel when it was announced. Under the indulgent eye of our hovering waiter and the restaurant manager, I had no alternative but to try it. I began with the duck web, which turned out to be more of an ankle - a tube of bone encased in a stocking of fat and skin. "It's a foot, you suck it," the manager explained encouragingly. I forced one down, gingerly sucking fat from bone, and as the colour drained from my cheeks, I could see Mel looking quietly triumphant.

The fish lips, too, were an acquired taste. Some of them resembled little strips of blubber, while others were recognisable mouths, shaped into startled "O"s. "Hmmm, it's nice - like abalone," I lied. But Mel wouldn't be tempted, and when I tried to ferry some onto his plate, he practically pushed me off in horror, yelping: "I've already said I don't want any!" He did think, however, that his wife, Anne Bancroft, would enjoy them. "She likes fish eyes, fish cheeks, all that stuff. And she married me - I'm the human equivalent of fish lips!"

The grand finale of the feast was a sea bass, steamed with ginger and spring onion, which arrived whole, lips and all. "Does anyone want the head?" our waiter asked, with no real hope in his voice. The fish was perfectly cooked and superbly fresh. "This is the hit of the meal!" exclaimed Mel. "I'll stick to this - you carry on with the feet and the lips."

We'd eaten an unfeasible amount, but still found room for a platter of fresh fruit, though we didn't fall into the trap of mistaking the hot scented towels for steamed pudding. "We didn't just order - we ate!" concluded Mel approvingly. Philippa and Alan agreed the food at New Diamond was better than any of the fancier Chinese restaurants they frequent. "Everything tasted of itself - very pure," as Alan said. Our bill came to a little over pounds 100 before the tip, which Mel smoothly supplemented by pressing an additional note into our waiter's hand.

When we got upstairs, we were rather relieved to have been put in the basement, as the main dining room now held a party of drunken men wearing bamboo steamers on their heads and shouting obscenities in silly voices. Small wonder that one of them had come over earlier to hail Mel as a comic genius. As we exited, the entire staff ceremoniously lined up to see us out. `"Thank you! Thank you!" cried Mel. "We'll be back! In an hour!"

New Diamond, 23 Lisle Street, London WC2 (0171-437 2517). Daily noon to 3am. Disabled access. All cards